As the number of older adults in the United States increases over the next 50 years, it is imperative that we understand not only those factors that are associated with limitations in functioning, but also those that are associated with maintained functioning and well-being. Recent research suggests that engagement in cognitively demanding activities is beneficial in terms of preserving cognitive health. For example, there is evidence that older adults who engage in social, leisure, and work-related activities that place demands on cognitive resources are more likely to maintain their intellectual competence over longer periods of time than those who do not engage in such activities. Given this relationship and the potential significance for public health issues, it is important to understand the factors associated with continued participation in cognitively demanding activities later in life. Of interst is the fact that certain characteristics of the individual that might be expected to predict participation and level of performance, such as ability, do not account for substantial variance between individuals in participation. In the present project, we investigate the strong possibility that age-related changes in motivation play a critical role in determining participation in demanding everyday activities, with perceived benefits and costs of engagement guiding decisions regarding participation. In the proposed research, we hypothesize that normative increases with age in the physical costs associated with cognitive activity-as indexed by cardiovascular responses-affect this benefit/cost analysis, with reductions in participation in later life related to increased costs. We also propose, however, that perceptions of the self- relevance of the task as well as one's beliefs about aging may also influence perceptions of benefits and costs. For example, negative perceptions about the impact of aging on ability may lead an individual to exaggerate the perceived costs of activities, thereby exacerbating the impact of costs on participation. Conversely, if an individual believes an activity is self-relevan (e.g., beneficial to cognitive health), motivation may be affected through adjustments in perceived benefits. Importantly, both self-relevance and beliefs about aging are potentially modifiable, which has implications for the development of effective interventions. Motivational factors have been relatively neglected in the study of cognitive aging. They may, however, play a critical role in determining late-life functioning and well-being. The proposed research will systematically explore (a) how normative age differences in the costs associated with cognitive activity influence motivation and subsequent activity participation, and (b) the factors that moderate this relationship.